The long term goals of this proposal are to elucidate signaling mechanisms associated with the activation and proliferation of vascular smooth muscle cells (SMC) from humans, focusing on a potential mediating role of nuclear factor-kB (NFkB), with the objective of realizing the degree to which interference in the NFkB pathway will alter key events involved in atherogenesis and other forms of vascular pathology. Aim I will ascertain the relative contribution of NFkB to activation of SMC in response to cytokines of established importance in vascular pathology. Indices of SMC activation include the production of interleukin-6, expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and Class II major histocompatibility antigens. To this end, inhibitors of NFkB activation (antioxidants and proteasome inhibitors) will be tested for their ability to suppress activation marker messenger RNA and protein expression. Aim II will ascertain the relative contribution of NFkB in mitogenic signaling of factors that stimulate the growth of SMC, such as platelet-derived growth factor, interleukin-1, and thrombin. Human SMC will be incubated with agonists in the absence or presence of NFk3 inhibitors, followed by determination of DNA synthesis, cell proliferation, and proto-oncogene messenger RNA expression. Involvement of NFkB will be verified by correlating the anticipated inhibitory influence of inhibitors with nuclear translocation and DNA binding of NFkB proteins following agonist stimulation.